This invention relates to a method and composition for cleaning of dairy equipment and briefly involves the adaptation of enzymatic dissolution of milk stone and other dairy deposits to the problems of maintaining dairy cleanliness.
The high nutritive value of milk has created enormous cleanliness and sterility problems for the dairy industry. To prevent microbial contamination, heat sterilization has become the prevalent method for maintaining wholesome the milk consumed in the United States. Yet, even high temperature short time (HTST) contact between milk and heated surfaces causes deposition of milk stone, which deposits interfere with heat exchange, and in addition, provides a locale for bacterial growth. As a consequence, dairy equipment, notably the sterilizers, are customarily cleaned at least once a day.
One cleaning technique, heretofore used widely, particularly for the CIP (cleaning in place) method, involves flushing the sterilizing equipment in alternation with a highly alkaline non-foaming detergent formulation and with a highly acidic phosphoric acid wash. During this cleaning cycle, the sterilizer is not allowed to cool down so that basically the cleaning action is accomplished by the alternation of hot alkaline detergent and hot phosphoric acid. Insofar as concerns the dairy and dairy equipment (usually stainless steel), such a cleaning cycle is efficient. Any fats in or on the dairy equipment are liquefied, saponified and removed by the hot alkaline wash. Calcium deposits are sequestered and removed by the hot phosphoric acid wash.
However such standard cleaning cycles, e.g. C.I.P. and HTST cycles, involve somewhat extreme pH conditions, such as for example pH 2-3 for the acid wash and pH 12-13 for the alkaline wash, with concommitantly relatively high mineral matter loading in the wash waters e.g. 0.5-2 ounces per gallon, roughly 10 g/l. The local sewage disposal plant must dispose of the nutrients in the wash waters, and the sewage plant effluent adds a significant mineral matter loading to downstream surface waters.
The importance of cleanliness in the dairy industry is such that dairies are largely exempt from the full force and effect of environmental statutes and regulations that would otherwise prohibit discharge of highly alkaline and highly acidic effluents into sewage disposal systems. The microorganisms in those sewage disposal systems receiving dairy effluents, are subject to a highly alkaline pH, and to a highly acid pH in rapid alternation, the latter including large quantities of phosphorous nutrient. In consequence, malfunctions often occur in the aerobic digesters of the sewage disposal systems. Indeed a significant tendency has been established for municipalities, one by one, to decline the responsibility for handling sewage effluent from the local dairy. More and more the dairy operator must accept the full responsibility for treatment of the dairy effluent. Yet the problem described above is exacerbated when the load of the sewage disposal system is almost entirely effluent from a dairy, and such is inevitably the case when a large dairy has been forced to provide its own sewage disposal system.
The object of the present invention is to provide an easily disposed of cleaning solution for dairies.
A further object of the present invention is to provide a cleaning procedure adopted to the removal of milk stone and other milk deposits from inside of dairy equipment.